Phenolic polyamino-amides capable of curing epoxy resins



United States Patent Oflice 3,382,261 PHENOLIC POLYAMINO-AMIDES CAPABLE F CURING EPOXY RESINS John B. Kittredge, White Bear Lake, Minn., and Albert L. Micchelli, Middletown, N.J., assignors to Minnesota Mining and Manufacturing Company, St. Paul, Minn., a corporation of Delaware No Drawing. Continuation-impart of application Ser. No. 176,428, Feb. 28, 1962. This application Jan. 3, 1966, Ser. No. 518,003

9 Claims. (Cl.260-404.5)

This invention relates to the preparation of new and useful phenolic polyamines and their use as co-reactants for epoxy resins. This application is a continuation-inpart of abandoned U.S. Ser. No. 176,428, filed Feb. 28, 1962.

It is an object of this invention to provide a new class of polyamines which contain a phenolic nucleus. These compounds react at room temperature with the epoxide linkages of epoxy resins more rapidly than those polyamines commonly used as co-reactants for epoxy resins. Furthermore, the phenolic nucleus of the polyamine becomes an integral part of the cured epoxy resin. These cured epoxy resins have excellent chemical resistance and physical properties, e.g.. adhesion to concrete, impact resistance, etc. Additional advantages of these compounds as co-reactants for epoxy resins reside in their low volatility and toxicity.

In general, these phenolic polyamines are prepared by reacting a polyamine with a phenolic-containing carboxylic acid to form the corresponding amine saltand by converting the amine salt to an amide upon heating to an elevated temperature to split otf and remove water. The phenol-containing carboxylic acid is prepared by the alkylation of a phenol with a carboxylic acid. The easiest and more economical alkylation is the addition ofan unsaturated carboxylic acid or compounds readily derived from these acids to the phenol, although known techniques for the metathesis of other carboxylic acids and their derivatives to the phenol nucleus are available.

Compounds which accomplish these objects and advantages have the structural formula RrCONH(CH CHzNH) XII where x is from 2 to about 15 (preferably 2-4) and R is a divalent straight-chain hydrocarbon radical, linking the phenolic nucleus and the terminal carboxyl group. The divalent straight-chain hydrocarbon radicalmay be saturated or unsaturated and may be branched chain.

It has also been discovered that in the preparation of these polyamines it is possible to select intermediates which result in a relatively more flexible cured epoxy resin than can be obtained with conventional polyamine cures. For this purpose, the acid used to prepare the polyamine is preferably an unsaturated fatty acid such as oleic, linoleic and linolenic or a source high in content of these acids such as the fatty acids derived from tall oil. In this manner polyamines of the formula RiC ONH(CH1CHZNEI) H where R is a seventeen-carbon hydrocarbon radical and x is 2 to about 15, are produced.

An especially preferred class is prepared using phenolic 3,382,261 Patented May 7, 1968 compounds found in cashew nut shell liquid to react with the unsaturated acid and polyamine to produce compounds of the formula where x is as above, R and R are straight-chain hydrocarbon radicals and the sum of the carbon atoms in R and R is at least 16 and most preferably 32, such as when an unsaturated fatty acid is also employed as an intermediate.

Phenols useful as intermediates include phenol, cresols, alkyl-phenol, resorcinol, Bis-phenol A, and cashew nut shell liquid. Cashew nut shell liquid is a natural product which varies in reactivity depending upon the source and processing treatment. Basically, it is a mixture of metasubstituted phenols, the substituents being a IS-carbon side chain containing 0 to 3 non-conjugated double bonds.

Unsaturated acids useful as intermediates include the above-enumerated fatty acids, acrylic acid, methacrylic undecylenic acid, and so forth.

Polyamines useful as intermediates include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and so forth. These polyamines generally have the structural formula where x is from 2 to about 15, preferably 2 to 4.

As employed in this specification, the term epoxy resin relates to poly-epoxide compounds which contain reactive vicinal epoxy linkages available as reaction sites. One type of epoxy resin which has enjoyed a high degree of commercial success is prepared from epichlorohydrin and polyhydric phenols, such as 2,2'-bi's-(p-hydroxy phenyl) propane (Bis-phenol A), resorcinol, and polyhydric novolak. A second class of epoxy resins is prepared from polyhydric alcohols such as glycerine and pentaerythritol and epichlorohydrin. Another class of epoxy resins is prepared from epiehlorohydrin and amines containing reactive hydrogen atoms. A still further class of epoxy resins is prepared by the direct epoxidation of aliphatic or aromatic unsaturated compounds. These resins and compositions containing these resins are classified by the Patent Office in Class 260, sub-classes 2, 42, 47 and 348, and reference thereto may be had for the early patents as well as the most recent patent publications on current developments in this field.

Because the above-mentioned classes of compounds are currently enjoying greater and greater commercial success, it is recognized that other epoxy resins containing an average vicinal epoxy group content of more than 1 will be developed that are useful in the practice of this invention. As with those epoxy resins, presently available, the preferred compounds are those containing more than 1 and less than 3 vicinal epoxy groups per molecule and mixtures containing a preponderance of these compounds.

It may also be desirable to add to filler to the compositions of this invention. Among those fillers useful in the practice of this invention are talc, silica, alumina, carbon particles, steel chips, steel filings, aluminum flake, calcium carbonate, thixotropic agents, fibrous fillers such as asbestos and chopped glass, and various other fillers commonly employed in combination with epoxy resins.

It is also contemplated that these co-reactants may be used in combination with conventional curing agents such as amines, anhydrides, mercaptans, and so forth. Likewise, if additional acceleration is required, conventional epoxy resins accelerators, such as tertiary amines, may be added.

In general, the phenolic polyamines of this invention are employed in a weight ratio of from one part by weight J phenolic polyamine to 10 parts by weight epoxy resin and 2 parts by weight phenolic polyamine to one part by weight epoxy resin. The preferred ratio is one part by weight phenolic polyamine to 1 to 2 parts by weight epoxy water of reaction formed during the conversion of the amine salt to the corresponding amide. The toluene was then stripped by vacuum from the resulting high molecular weight phenoliopolyamine which had a viscosity of resin when the phenolic polyamine is used as the sole co- 5 4,060 centipoises. This phenolic-polyamine reacted at reactant. room temperature with e oxy resins, For example, EPON This invention may be illustrated further by reference to 828, an epoxy resin (epoxy equivalent of about 190; 2,2- the following examples in which all parts are expressed his (4 hydroxyphenyl) propane), product of Shell as parts by weight and all percentages are expressed Chemical Company (75 grams), and 25 grams of the as percent by weight, unless specified otherwise. phenolic-polyamine were cured for 16 hours at room tem- Examplel perature to produce a patty havmg a Shore hardness or 00. By changing the ratio to 55 parts by weight epoxy i b Shall hquld (50.1mm by f tan 011 resin to 45 parts phenolic-polyaminc, a Shore D hardness fatty acid pitch (50 parts by weight), and htharge (1 part of 70 was Obtained by weight) were reacted at 500 F., for 23 hours at Example IV which time the fluidity of the mixture was 15.5 cm./l30 F. as measured by melting a sample at 130 F. and de- A Phbhohc mlxthrc Comprising 50% 0436501, termining its flow down an 85 incline over a period of Phenol, and 5% alkylated Phenol Paris y s one minute. Toluene (45 parts by weight) and diethylenef g-rp Complbx Parts y Welght) W@r@ m1Xcd triamine (18.1 parts by weight) were added to the reaction 00 sultabhi Vessel and heated to A tall 011 fatty mixture (105 parts by weight) to form the amine salt. acid mixture, haylhg an acld hufflbef of 190 p f The admixture was refluxed for 6 hours to remove water y weight), was added Over a Perlod of one hbhf- Durlhg by azeotropic distillation with the conversion to amide. the first half h of addition, the tempefflhlrc in the The resulting ii l i was stripped f toluene vessel was maintained at 40 C.; during the second half A mixture f hi h 1i 1 i 224 parts by 7 hour the temperature was raised slowly to 49 C. When weight) and an epoxy resin, a reaction product of Bishe addition was completed, the temperature of the rephenol A and epichlofohydfin having an epoxy equiva. actants VVZIS raised to 66 and for one hour, then lency Of 190 (190 parts by weight) we cured f r 4 hours raised to 93 C. and held for one hour. Unreacted maat 115 C Aft b i immersed i water and aquaterials were removed by distillation under vacuum at a ous acetic acid for seven days, the percent adsorption of 90 P temperature of 125/15 h yleld Wil5 h samplcs as measured b h i increase i i h was 800 grams of the phenol-acid condensate WhlClI contalned 0.55% and 8.30%, respectively. 26% y Weight bound P The phenol-acid-condensate (480 parts by weight) was Example H dissolved in toluene (120 parts by weight) and tricthyl- Acid-Washed cashew nut Shell liquid P3115 by enetetramine (219 parts by weight) was added to form g a mixture 0f C18 unsamfatbd fatty acids the amine salt. The mixture was then heated to reflux, Paris y Weight) and cresol Sulfohic acid Parts by and over a period of 2 /2 hours one mole of water per weight) were reacted at 300 F. for 6 /2 hours at which mole f carboxyl group was collected in a Dean and time a Viscosity of 19,300 cehtipoises at was Stark trap. The product was then stripped of toluene unscrved- The resulting y 'p y Parts y der vacuum at a pot temperature of 300 F./40 mm. Hg. Weight) and triethylenetetralhine Parts y Weight) 40 Table I shows the results of reacting an epoxy resin were reacted at 300 Rim 2 hours in the pf n prepared from Bis-phenol A and epichlorohydrin having toluene (300 parts by weight) to form initially the amine an epoxy equivalency of 180 (100 parts by weight) with 5111i and then remove y illeotropic distillation the the phenolic polyamines of this example in the indicated Water of macho" formed during the Conversion of the amounts. Also included in Table I is comparative data amine salt to the corresponding amide. The toluene was f cured epoxy resins prepared f o the phenolic-acid pp y Vacuum b the resulting high molec' and a polyamine mixture, i.e. the amine salt, used to Weight bhehohb'polyamlhb which had a Viscosity of prepare the phenolic-polyamine of this example. In those 22,300 centipolscs. samples where an acceleration was added, the accelerator Example 111 was 2,4,6-tri (dimethyl amino methyl) phenol. All Acid-washed cashew nut shell liquid (750 parts by samples were cured at room temperature for 16 hours and weight) and a mixture of unsaturated fatty acids (750 then posteured at 140 F. for two hours.

TABLE I (Io-reactant Phenolie-Polyamiue Unreaetcd Acid and Iolyzmine Parts by Weight (o-reactant 40 40 40 s0 0 S0 40 40 40 S0 80 80 Parts by Weight Accelerator 0 2 4 0 2 4 0 4 0 2 4 Imm rsion in Toluene for 24 hours:

Hardness: l

Original. 79 s0 s0 79 79 7s 77 77 so 71 73 70 Final... so so 79 7s 7s 35 73 7s 30 20 an Absorption 6.66 0. 25 0.34 ass 0. 75 0.60 F a. 71 0.00 F F F Immersion in Xylene, Isopropanol and Naphtha: 3

llarducs l 79 so so 79 7a 77 7a 70 72 72 72 Fina 05 71 70 09 0.3 04 42) n2 67 4Q 49 4a Absorption 7. 0a 3.73 4.41 4.53 4. 83 6.21 F 7. 09 5 3-: F I 1 1 Shore I). 2 Percent by weight increase after immersion in toluene. 3 Equal volume of each. F=Failcd test by disintegration. parts by Weight) and cresol sulfonic acid (90 parts by EXAMPLE V weight) were reacted at 300 F. for 3 hours at which 70 A phenolic mixture comprising 50% o-crcso], 45%

time a viscosity of 10,200 centipoises at 25 C. was observed. The resulting carboxyl-phenol (532 parts by weight) and triethylenetetramine (171 parts by weight) were reacted at 300 F., for 2 hours in the presence of toluene (300 parts by weight) to form initially the amine salt and then to remove by azeotropic distillation the phenol and 5% alkylated phenol (966 parts by weight), a tall oil fatty acid mixture with an acid number of 190 (148 parts by weight), and triethyicnetetramine parts by weight) were dissolved in toluene (38 parts by weight). The mixture was heated to rellux over a period of two EXAMPLE VI For certain applications Where impact resistance is of more importance than chemical resistance, c.g. potting compounds and structural adhesives, a softer cured epoxy product is desired. Such cured products can be prepared by using phenolic-polyamines or phenolic polyamine salts prepared from the higher molecular weight polyamines. The following example illustrates the preparation of such cured products.

300 grams of tall oil fatty acid (acid number 190) were mixed in a suitable vessel with 125 grams of 92% phenol- 8% o-cresol and 2.5 grams of 95% sulfuric acid and mixed with stirring at 300310 F. for 45 minutes. 100 grams of turpentine gum was then added to alkylate the remaining unreacted phenol and plasticize the final product. To neutralize the residual acid 1.5 grams of finely divided calcium oxide was added with agitation, then the mixture was cooled to 100 F. and filtered to produce the phenol-acid condensate. 48 grams of the phenol-acid condensate and 12 grams of a polyamine having a number average molecular weight of 600 and an average of about 14 recurring CH CH NH units per molecule (Polyethyleneimine NC-1234, Dow Chemical Co.) were mixed together to form the corresponding phenolic-polyamine salt. To remove water and convert the salt to the corresponding phenolic-polyamine toluene was added to the phenolic-polyamine salt, and the mixture was refluxed at 300 F. for about 2 hours to remove water by azeotropic distillation. After the water was completely eliminated, the toluene was stripped off by heating under vacuum.

One sample (Sample A) was prepared by mixing 100 parts by weight of Epon 828, described earlier, with 60 parts by weight of the above phenolic-polyamine salt and allowed to cure for seven days at room temperature. Another sample (Sample B) was prepared by mixing 100 parts by weight of Epon 828 with 60 parts by weight of the above phenoliopolyamine and allowed to cure for seven'days at room temperature. Samples A and B both had a Shore D hardness of 73, indicating relatively high impact resistance.

Various other embodiments of the present invention will be apparent to those skilled in the art without departing from the scope thereof.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. As a composition capable of crosslinking epoxy resins, a phenolic polyamine having the formula where x is 2 to about 15 and R is a straight chain aliphatic hydrocarbon radical having at least two carbon atoms and having a phenolic substituent of the formula wherein R is an aliphatic hydrocarbon radical having from 1 to carbon atoms and n is 0 or 1, the sum of the carbon atoms in R and R being from 16 to 32.

2. As a composition capable of crosslinking epoxy resins, a phenolic polyamine having the formula R CONH(CH CH NH) H where R is a straight chain aliphatic hydrocarbon radical having at least two carbon atoms and having a phenolic substituent of the formula 0 wherein R is an aliphatic hydrocarbon radical having Cir where x is from 2 to about 15 and R is a straight chain aliphatic hydrocarbon radical having at least two carbon atoms and having a phenolic susbtituent of the formula where R is an aliphatic hydrocarbon radical having from 1 to 15 carbon atoms and n is O or 1, the sum of the carbon atoms in R and R being from 16 to 32.

7. The phenolic polyamine salt of claim 6 wherein x is 2 to 4.

8. An amine salt of a polyamine having the formula wherein x is 2 to about 15, and an alkylated phenol of the formula it 2) RIC OH wherein R is a straight chain aliphatic hydrocarbon radical having at least two carbon atoms, R is an aliphatic hydrocarbon radical having from 1 to 15 carbon atoms, 11 is 0 or 1, and the sum of the carbon atoms in R and R being from 16 to 32.

9. The amine salt of claim 8 wherein n is 2 to 4.

No references cited.

NICHOLAS S. RIZZO, Primazy Examiner.

F. A. MIKA, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,382,261 May 7, 1968 John B. Kittredge et al.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 3, line 39, "phenyl" should read phenol line 71, "532" should read 358 Columns 3 and 4, TABLE I, ninth column, line 6 thereof, "79" should read 77 Signed and sealed this 28th day of October 1969.

(SEAL) Attest:

k Edward M. Fletcher, 1n, WILLIAM E. SCHUYLER, JR-

Attesting Officer Commissioner of Patents 

1. AS A COMPOSITION CAPABLE OF CROSSLINKING EPOXY RESINS, A PHENOLIC POLYAMINE HAVING THE FORMULA R1CONH(CH2CHNH)XH WHERE X IS 2 TO ABOUT 15 AND R1 IS A STRAIGHT CHAIN ALIPHALIC HYDROCARBON RADICAL HAVING AT LEAST TWO CARBON ATOMS AND HAVING A PHENOLIC SUBSTITUENT OF THE FORMULA 